Ink, ink container, inkjet recording method, inkjet recording device, and recorded matter

ABSTRACT

An ink includes a solvent and a resin, wherein the storage elastic modulus G1 of an ink film obtained by drying the ink is 2.0×10 8 -5.0×10 8  Pa at 20 degrees C. as measured by a dynamic viscoelasticity measuring method and the ratio (G2/G1) of the storage elastic modulus G1 to the storage elastic modulus G2 of the ink film measured at 80 degrees C. by the dynamic viscoelasticity measuring method is 0.30-0.85.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. application Ser. No.15/297,646, filed on Oct. 19, 2016, which is based on and claimspriority pursuant to 35 U.S.C. § 119 to Japanese Patent Application Nos.2015-221586, 2015-221574, and 2016-127955, filed on Nov. 11, 2015, Nov.11, 2015, and Jun. 28, 2016, respectively, in the Japan Patent Office,the entire disclosure of which is hereby incorporated by referenceherein.

BACKGROUND Technical Field

The present invention relates to an ink, an ink container, an inkjetrecording method, an inkjet recording device, and recorded matter.

Description of the Related Art

Image quality demanded for inkjet recording methods is on a par with theimage quality of offset printing even when images are printed on coatedpaper, which is used in commercial printing and has poor inkabsorbability. For example, ink including resin particles obtained bypolymerizing a mixture including a monomer having an alkoxy silyl groupis proposed.

SUMMARY

According to the present invention, provided is an improved ink whichincludes a solvent and a resin. The storage elastic modulus G1 of an inkfilm obtained by drying the ink is 2.0×10⁸-5.0×10⁸ Pa at 20 degrees C.as measured by a dynamic viscoelasticity measuring method and the ratio(G2/G1) of the storage elastic modulus G1 to the storage elastic modulusG2 of the ink film measured at 80 degrees C. by the dynamicviscoelasticity measuring method is 0.30-0.85.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Various other objects, features and attendant advantages of the presentinvention will be more fully appreciated as the same becomes betterunderstood from the detailed description when considered in connectionwith the accompanying drawings in which like reference charactersdesignate like corresponding parts throughout and wherein:

FIG. 1 is a perspective diagram illustrating an example of an inkjetrecording device; and

FIG. 2 is a perspective diagram illustrating an example of the main tankin the inkjet recording device.

The accompanying drawings are intended to depict example embodiments ofthe present invention and should not be interpreted to limit the scopethereof. The accompanying drawings are not to be considered as drawn toscale unless explicitly noted. Also, identical or similar referencenumerals designate identical or similar components throughout theseveral views.

DESCRIPTION OF THE EMBODIMENTS

In describing embodiments illustrated in the drawings, specificterminology is employed for the sake of clarity. However, the disclosureof this specification is not intended to be limited to the specificterminology so selected and it is to be understood that each specificelement includes all technical equivalents that have a similar function,operate in a similar manner, and achieve a similar result.

As used herein, the singular forms “a”, “an”, and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

Moreover, image forming, recording, printing, modeling, etc. in thepresent disclosure represent the same meaning.

The ink of the present disclosure includes a solvent, a resin, and otheroptional components. The storage elastic modulus G1 of an ink filmobtained by drying the ink is 2.0×10⁸-5.0×10⁸ Pa at 20 degrees C. asmeasured by a dynamic viscoelasticity measuring method and the ratio(G2/G1) of the storage elastic modulus G1 to the storage elastic modulusG2 of the ink film measured at 80 degrees C. by the dynamicviscoelasticity measuring method is 0.30-0.85.

The storage elastic modulus G1 of the ink film at 20 degrees C. is2.0×10⁸-5.0×10⁸ Pa and preferably 2.5×10⁸-4.0×10⁸ Pa. In addition, theratio (G1/G2) is 0.30-0.85 and preferably 0.4-0.7.

When the storage elastic modulus G1 is 2.0×10⁸ Pa or greater, the glosslevel and blocking resistance of images are good. When the storageelastic modulus G1 is 5.0×10⁸ Pa or less, abrasion resistance of imagesare improved. When the ratio (G1/G2) is 0.30 or greater, blockingresistance of images is good. When the ratio is 0.85 or less, the glosslevel of images is improved.

The storage elastic modulus G3 of the ink film at −20 degrees C. asmeasured by the dynamic viscoelasticity measuring method is preferably1.0×10⁹ Pa or greater and more preferably 2.0×10⁹ Pa. When the storageelastic modulus G3 is 1.0×10⁹ Pa or greater, abrasion resistance ofimages is improved.

In addition, in terms of abrasion resistance of images, it is preferablethat the storage elastic modulus G3 be 3.0×10⁸ to less than 1.0×10⁹ Paand the storage elastic modulus G4 at −40 degrees C. be 1.0×10⁹ Pa orgreater. It is more preferable that the storage elastic modulus G3 be4.0×108-8.0×10⁸ Pa and the storage elastic modulus G4 be 2.0×10⁹ Pa orgreater.

The storage elastic moduli G1, G2, G3, and G4 can be controlled by themass average molecular mass, the average degree of polymerization, andthe glass transition temperatures of the resin, and introduction ofcross-linking structure to adjust those values within the rangesmentioned above.

The mass average molecular mass and the average degree of polymerizationcan be controlled by an initiator or a chain transfer agent in the caseof a chain polymerization resin and, the ratio of functional groups, inthe case of resins obtained by polycondensation or polyaddition.

The glass transition temperature can be mainly controlled by the monomercomposition. However, if the glass transition temperature is outside therange specified later, it may be difficult to set the storage elasticmodulus G1 and G2/G1 within the ranges mentioned above.

To set the storage elastic modulus G1 and the ratio (G1/G2) within theranges, it is preferable for the resin to have a cross-linking structureby a cross-linking agent such as a polyfunctional monomers. However, ifthe condensation of the cross-linking agent is too high, the storageelastic moduli G1 and G2 increase, which makes it difficult to satisfythe value ranges mentioned above. In addition to the concentration ofthe cross-linking agent, if there is a factor having an impact on thespeed of cross-linking reaction, the factor is required to be adjusted.For example, as described in Examples described later, it is notpossible to satisfy the value ranges specified above by analkoxysilane-based compound because cross-linking reaction proceedsexcessively if pH during polymerization is too low.

The storage elastic moduli G1, G2, G3, and G4 can be measured under thefollowing conditions.

First, the ink is dried for 48 hours at 100 degrees C. in a constanttemperature tank employing heated wind circulation system to obtain anink film having a thickness of about 0.3 mm, which is cut to a size of alength of about 30 mm and a width of about 10 mm. Thereafter, the inkfilm is measured by using ARES-G2 (manufactured by TA Instruments) witha freezer. After the sample of the ink film is set in a device at 20degrees C. using a torsion solid clamp as a jig for fixing a sample, thesample is cooled down to −60 degrees C. under an auto tension of 2 g. 10minutes after the temperature reaches −60 degrees, the sample ismeasured under the following conditions. Based on the obtained measuringdata, the storage elastic modulus at 20 degrees C. is defined as G1, thestorage elastic modulus at 80 degrees C. is defined as G2, the storageelastic modulus at −20 degrees C. is defined as G3, and the storageelastic modulus at −40 degrees C. is defined as G4.

Measuring Conditions

Measuring mode: temperature sweep

Measuring range of temperature: −60-100 degrees C.

Temperature rising speed: Heating speed: 5 degrees C./min

Frequency: 1 Hz

Initial distortion: 0.1 percent

Auto tension: 2 g

The content of the tetrahydrofuran (THF) soluble portion of the rein inthe ink film is 20-50 percent by mass and preferably from 25 to 40percent by mass.

When the content of the THF soluble portion is 20 percent by mass orgreater, smear fixability is improved. When the content of the THFsoluble portion is 50 percent by mass or less, gloss level is improvedand image density becomes good.

The content of the THF soluble portion of the rein in the ink film canbe measured in the following manner.

First, ink is dried for 1 day at 100 degrees C. in a constanttemperature tank employing heated wind circulation system to obtain anink film having a thickness of about 0.3 mm, which is cut to a size of alength of about 50 mm and a width of about 10 mm.

The ink film cut to the size is dipped in 50 g of deionized water andmaintained at 50 degrees C. for one day. Thereafter, the ink film istaken out from the deionized water and dried at 50 degrees C. for oneday.

Next, about 30 mg of the ink film subjected to dipping treatment withdeionized water is placed in an aluminum sample container, which is setin a thermogravimetric analyzer (SHIMADZU DTG-60, manufactured byShimadzu Corporation), and measured in a nitrogen atmosphere in thefollowing conditions.

Measuring Conditions

Temperature is raised from 40 to 100 degrees C. as a temperature risingspeed of 10 degrees/minute.

Maintained at 100 degrees C. for 10 minutes

Temperature is raised from 100 to 500 degrees C. as a temperature risingspeed of 10 degrees/minute.

Maintained at 500 degrees C. for 10 minutes

Thereafter, based on the obtained measuring results, the content R(percent by mass) of the resin in the ink film can be calculated fromthe mass M1 (mg) obtained after 10 minutes at 100 degrees C. and themass M2 (mg) obtained after 10 minutes at 500 degrees C.

R=(M1−M2)/M1×100

1 g of the dried film obtained after dipping treatment with deionizedwater is dipped in 10 g of THF and maintained at room temperature forone day.

The supernatant of the dip coated liquid is dried at 150 degrees C. for3 hours in a drier and the THF soluble portion (percent) of the resin inthe dried film is calculated assigning the masses before and afterdrying into the following relation.

In the following relation, M3 (g) is the mass of the dried film dippedin THS, M4 (g) is the mass of THF for use in dipping the dried film, M5(g) is the mass of the supernatant of the dried dipping liquid, and M6(g) is the mass after drying.

T=(M4×M6)/(M3×M5)×100

Based on the content R of the resin in the ink film and the THF solubleportion T (percent) of the resin in the dried film, the THF solubleportion of the resin contained in the dried film obtained by drying theink of the present disclosure is calculated according to the followingrelation.

THF soluble portion of the resin contained in the dried film obtained bydrying the ink of the present disclosure=T/R×100

The glass transition temperature of the THF soluble portion is −20 to 20degrees C. and more preferably −10 to 10 degrees C. as measured by DSC.

When the glass transition temperature is outside the range of from −20to 20 degrees C., blocking resistance may deteriorate.

The glass transition temperature can be measured by DSC SYSTEM Q-2000(manufactured by TA INSTRUMENTS. JAPAN).

Specifically, about 5.0 mg of a resin placed in an aluminum samplecontainer is set in an instrument to conduct measuring in nitrogenatmosphere under the following conditions.

A DSC curve at the second temperature rising is selected and the glasstransition temperature is obtained by the midpoint method.

Hold 5 minutes after cooled down to −70 degrees C.

Raise the temperature to 120 degrees C. at a temperature raising speedof 10 degrees C./min.

Hold 5 minutes after cooled down to −70 degrees C.

Raise the temperature to 120 degrees C. at a temperature raising speedof 10 degrees C./min.

The mass average molecular mass obtained by gel permeationchromatography (GPC) of the THF soluble portion is preferably200,000-900,000 and more preferably 300,000-700,000 to improve smearfixability and gloss level.

When the mass average molecular mass is 200,000-900,000, blockingresistance is good and smear fixability and gloss level are improved.

The mass average molecular mass can be measured by using a gelpermeation chromatography (GPC) measuring device (for example, HLC-8220GPC, manufactured by TOSOH CORPORATION).

The column used is TSKgel Super HZM-M 15 cm triplet (manufactured byTOSOH CORPORATION).

The resin to be measured is dissolved in THF to obtain a 0.15 percent bymass THF solution (including a stabilizer, manufactured by WAKO PURECHEMICAL INDUSTRIES, LTD.) followed by filtration using a filter havingan opening of 0.2 μm. The resultant filtrate is used as a sample.

100 μl of the THF sample solution is injected into the measuringinstrument and the measuring is conducted under the condition that thetemperature is 40 degrees C. and the flow speed is 0.35 mL/min.

The mass average molecular weight is calculated by using a standardcurve created by a mono-dispersed polystyrene standard sample.

As the mono-dispersed polystyrene standard sample, Showdex STANDARDSERIES (manufactured by SHOWA DENKO K.K.) and toluene are used.

THF solutions of the following three kinds of mono-dispersed polystyrenestandard samples are prepared and the measuring is conducted under theconditions specified above to create a standard curve by defining themaintaining time of the peak top as the light scattering molecular massof the mono-dispersed polystyrene standard samples.

Solution A: S-7450 2.5 mg, S-678 2.5 mg, S-46.5 2.5 mg, S-2.90 2.5 mg,and THF 50 mL

Solution B: S-3730 2.5 mg, S-257 2.5 mg, S-19.8 2.5 mg, S-0.580 2.5 mg,and THF 50 mL

Solution C: S-1470 2.5 mg, S-112 2.5 mg, S-6.93 2.5 mg, S-2.90 2.5 mg,and THF 50 mL

A refractive index (RI) detector is used as the detector.

THF insoluble portion of the resin contained in the ink film ispreferably cross-linked by a polyfunctional monomer, etc. in terms ofblocking resistance.

Ink

The ink includes a solvent and a resin and preferably a coloringmaterial and other optional components.

The solvent preferably includes water and an organic solvent.

Organic solvents, water, coloring materials, resins, and additives foruse in the ink are described next.

Organic Solvent

There is no specific limitation on the type of the organic solvent usedin the present disclosure. For example, water-soluble organic solventsare suitable. Examples are polyols, ethers such as polyol alkylethersand polyol arylethers, nitrogen-containing heterocyclic compounds,amides, amines, and sulfur-containing compounds.

Specific examples of the water-soluble organic solvents include, but arenot limited to, polyols such as ethylene glycol, diethylene glycol,1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol,1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butane diol, triethyleneglycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol,1,3-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol,1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol,1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol,ethyl-1,2,4-butane triol, 1,2,3-butanetriol,2,2,4-trimethyl-1,3-pentanediol, and petriol; polyol alkylethers such asethylene glycol monoethylether, ethylene glycol monobutylether,diethylene glycol monomethylether, diethylene glycol monoethylether,diethylene glycol monobutylether, tetraethylene glycol monomethylether,and propylene glycol monoethylether; polyol arylethers such as ethyleneglycol monophenylether and ethylene glycol monobenzylether;nitrogen-containing heterocyclic compounds such as 2-pyrolidone,N-methyl-2-pyrolidone, N-hydroxyethyl-2-pyrolidone,1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone;amides such as formamide, N-methylformamide, N,N-dimethylformamide,3-methoxy-N,N-dimethyl propioneamide, and 3-buthoxy-N,N-dimethylpropioneamide; amines such as monoethanolamine, diethanolamine, andtriethylamine; sulfur-containing compounds such as dimethyl sulfoxide,sulfolane, and thiodiethanol; propylene carbonate, and ethylenecarbonate.

Since the water-soluble organic solvent serves as a humectant and alsoimparts a good drying property, it is preferable to use an organicsolvent having a boiling point of 250 degrees C. or lower.

Polyol compounds having eight or more carbon atoms and glycol ethercompounds are also suitable. Specific examples of the polyol compoundshaving eight or more carbon atoms include, but are not limited to,2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.

Specific examples of the glycolether compounds include, but are notlimited to, polyol alkylethers such as ethyleneglycol monoethylether,ethyleneglycol monobutylether, diethylene glycol monomethylether,diethyleneglycol monoethylether, diethyleneglycol monobutylether,tetraethyleneglycol monomethylether, propyleneglycol monoethylether; andpolyol arylethers such as ethyleneglycol monophenylether andethyleneglycol monobenzylether.

The polyol compounds having eight or more carbon atoms and glycolethercompounds enhance permeability of ink when paper is used as a printmedium.

The proportion of the organic solvent in ink has no particular limit andcan be suitably selected to suit a particular application.

In terms of the drying property and discharging reliability of the ink,the proportion is preferably 10-60 percent by mass and more preferably20-60 percent by mass.

Water

The proportion of water in the ink has no particular limit and can besuitably selected to suit to a particular application. In terms of thedrying property and discharging reliability of the ink, the proportionis preferably 10-90 percent by mass and more preferably 20-60 percent bymass.

Coloring Material

The coloring material has no particular limit. For example, pigments anddyes are usable.

The pigment includes inorganic pigments and organic pigments. These canbe used alone or in combination. In addition, it is possible to use amixed crystal.

As the pigments, for example, black pigments, yellow pigments, magentapigments, cyan pigments, white pigments, green pigments, orangepigments, gloss pigments of gold, silver, etc., and metallic pigmentscan be used.

As the inorganic pigments, in addition to titanium oxide, iron oxide,calcium oxide, barium sulfate, aluminum hydroxide, barium yellow,cadmium red, and chrome yellow, carbon black manufactured by knownmethods such as contact methods, furnace methods, and thermal methodscan be used.

As the organic pigments, it is possible to use azo pigments, polycyclicpigments (phthalocyanine pigments, perylene pigments, perinone pigments,anthraquinone pigments, quinacridone pigments, dioxazine pigments,indigo pigments, thioindigo pigments, isoindolinone pigments, andquinophthalone pigments, etc.), dye chelates (basic dye type chelates,acid dye type chelates, etc.), nitro pigments, nitroso pigments, andaniline black can be used. Of these pigments, pigments having goodaffinity with solvents are preferable. Also, hollow resin particles andhollow inorganic particles can be used.

Specific examples of the pigments for black include, but are not limitedto, carbon black (C.I. Pigment Black 7) such as furnace black, lampblack, acetylene black, and channel black, metals such as copper, iron(C.I. Pigment Black 11), and titanium oxide, and organic pigments suchas aniline black (C.I. Pigment Black 1).

Specific examples of the pigments for color include, but are not limitedto, C.I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellowiron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104, 108, 109,110, 117, 120, 138, 150, 153, 155, 180, 185, and 213; C.I. PigmentOrange 5, 13, 16, 17, 36, 43, and 51; C.I. Pigment Red 1, 2, 3, 5, 17,22, 23, 31, 38, 48:2, 48:2 {Permanent Red 2B(Ca)}, 48:3, 48:4, 49:1,52:2, 53:1, 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83,88, 101 (rouge), 104, 105, 106, 108 (Cadmium Red), 112, 114, 122(Quinacridone Magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178,179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, and264; C.I. Pigment Violet 1 (Rohdamine Lake), 3, 5:1, 16, 19, 23, and 38;C.I. Pigment Blue 1, 2, 15 (Phthalocyanine Blue), 15:1, 15:2, 15:3,15:4, (Phthalocyanine Blue), 16, 17:1, 56, 60, and 63; C.I. PigmentGreen 1, 4, 7, 8, 10, 17, 18, and 36.

The type of dye is not particularly limited and includes, for example,acidic dyes, direct dyes, reactive dyes, basic dyes. These can be usedalone or in combination.

Specific examples of the dye include, but are not limited to, C.I. AcidYellow 17, 23, 42, 44, 79, and 142, C.I. Acid Red 52, 80, 82, 249, 254,and 289, C.I. Acid Blue 9, 45, and 249, C.I. Acid Black 1, 2, 24, and94, C. I. Food Black 1 and 2, C.I. Direct Yellow 1, 12, 24, 33, 50, 55,58, 86, 132, 142, 144, and 173, C.I. Direct Red 1, 4, 9, 80, 81, 225,and 227, C.I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, and 202,C.I. Direct Black 19, 38, 51, 71, 154, 168, 171, and 195, C.I. ReactiveRed 14, 32, 55, 79, and 249, and C.I. Reactive Black 3, 4, and 35.

The proportion of the coloring material in ink is preferably 0.1-15percent by mass and more preferably 1-10 percent by mass in terms ofenhancement of image density, fixability, and discharging stability.

To disperse a pigment in ink, for example, a hydrophilic functionalgroup is introduced into the pigment to prepare a self-dispersiblepigment, the surface of the pigment is coated with a resin, or adispersant is used to disperse the pigment.

As a method of introducing a hydrophilic functional group into a pigmentto prepare a self-dispersible pigment, it is possible to use, forexample, a self-dispersion pigment, etc. in which a functional groupsuch as a sulfone group and a carboxyl group is added to a pigment(e.g., carbon) to make it dispersible in water.

To coat the surface of the pigment with a resin, the pigment isencapsulated by microcapsules to make the pigment dispersible in water.This can be referred to as a resin-coated pigment. In this case, all thepigments to be added to ink are not necessarily coated with a resin.Pigments partially or wholly uncovered with a resin may be dispersed inthe ink unless the pigments have an adverse impact.

In a method of using a dispersant to disperse a pigment, for example, aknown dispersant of a small molecular weight or a large molecularweight, which is represented by a surfactant, is used to disperse thepigment in ink.

As the dispersant, it is possible to select, for example, an anionicsurfactant, a cationic surfactant, a nonionic surfactant, an amphotericsurfactant, etc. depending on a pigment.

Also, a nonionic surfactant (RT-100, manufactured by TAKEMOTO OIL & FATCO., LTD.) and a formalin condensate of naphthalene sodium sulfonate aresuitable as the dispersant.

Those can be used alone or in combination.

Pigment Dispersion

A coloring material may be mixed with materials such as water and anorganic solvent to obtain ink. It is also possible to mix a pigment withwater, a dispersant, etc., first to prepare a pigment dispersion andthereafter mix the pigment dispersion with materials such as water andorganic solvent to manufacture ink.

The pigment dispersion can be obtained by dispersing water, a pigment, apigment dispersant, and other optional components and adjusting theparticle size. It is good to use a dispersing device for dispersion.

The particle diameter of the pigment in the pigment dispersion has noparticular limit. For example, the maximum frequency in the maximumnumber conversion is preferably 20-500 nm and more preferably 20-150 nmto improve dispersion stability of the pigment and amelioratedischarging stability and image quality such as image density. Theparticle diameter of the pigment can be measured using a particle sizeanalyzer (Nanotrac Wave-UT151, manufactured by MicrotracBEL Corp).

In addition, the proportion of the pigment in the pigment dispersion isnot particularly limited and can be suitably selected to suit aparticular application. In terms of improving discharging stability andimage density, the proportion is preferably 0.1-50 percent by mass andmore preferably 0.1-30 percent by mass.

It is preferable that the pigment dispersion be filtered with a filter,a centrifuge, etc. to remove coarse particles and thereafter degassed.

Resin

The type of the resin contained in ink has no particular limit and canbe suitably selected to suit to a particular application. Specificexamples thereof include, but are not limited to, urethane resins,polyester resins, acrylic resins, vinyl acetate-based resins,styrene-based resins, butadiene-based resins, styrene-butadiene-basedresins, vinyl chloride-based resins, acrylic styrene resins, and acrylicsilicone-based resins.

Resin particles formed of such resins may be also used. It is possibleto mix a resin emulsion in which the resin particles are dispersed inwater serving as a dispersion medium with materials such as a coloringmaterial and an organic solvent to obtain ink. The resin particle can besynthesized or is available on the market. These can be used alone or incombination of the resin particles.

The resin preferably includes resin particles formed of an acrylic resinor an acrylic styrene resin in terms of abrasion resistance of imagesand storage stability for an extended period of time of ink.

The resin is preferably cross-linked by a polyfunctional monomer, etc.If a non-cross-linked resin particle is used, gloss level and blockingresistance may deteriorate.

Specific examples of the polyfunctional monomers include, but are notlimited to, divinyl monomers such as divinyl benzene and ethylene glycoldimethactylate in the case of resins prepared by radical polymerizablemonomers, monomers having reactive functional groups such asglycidylmethacrylate and vinyltrimethoxy silane, and monomers such astrimethylol propane in the case of polyesters and polyurethanes.

The resin preferably includes a structure derived from a reactiveemulsifier. Usage of such a reactive emulsifier enhances storagestability of ink.

There is no specific limitation to the reactive emulsifier and it can besuitably selected to suit to a particular application. For example,emulsifiers having radical polymerizable double bonds are particularlypreferable. The reactive emulsifiers are available on the market.

Specific examples of the products available on the market include,LATEMUL 5-180 (manufactured by Kao Corporation), ELEMINOL JS-2(manufactured by Sanyo Chemical Industries, Ltd.), and AQUALON RN-20(manufactured by DKS Co. Ltd.).

The mass average molecular mass when the resin is non-cross-linked ispreferably 200,000-900,000 and more preferably 300,000-700,000. When themass average molecular mass is 200,000-900,000, blocking resistance isgood and smear fixability and gloss level are improved.

The mass average molecular mass of the resin can be measured by using agel permeation chromatography (GPC) measuring device (for example,HLC-8220 GPC, manufactured by TOSOH CORPORATION).

The column used is TSKgel Super HZM-M 15 cm triplet (manufactured byTOSOH CORPORATION). The resin to be measured is dissolved to obtain a0.15 percent by mass solution of tetrahydrofuran (THF) (containing astabilizer, manufactured by WAKO PURE CHEMICAL INDUSTRIES, LTD.)followed by filtration using a filter having an opening of 0.2 μm. Theresultant filtrate is used as a sample. 100 μl of the THF samplesolution is injected into the measuring instrument under the conditionthat the temperature is 40 degrees C. and the flow speed is 0.35 mL/min.

The molecular mass is calculated by using a standard curve created by amono-dispersed polystyrene standard sample. As the mono-dispersedpolystyrene standard sample, Showdex STANDARD SERIES (manufactured bySHOWA DENKO K.K.) and toluene are used. THF solutions of the followingthree kinds of mono-dispersed polystyrene standard samples are preparedand measuring is conducted under the conditions specified above tocreate a standard curve by defining the maintaining time of the peak topas the light scattering molecular mass of the mono-dispersed polystyrenestandard samples.

Solution A: S-7450 2.5 mg, S-678 2.5 mg, S-46.5 2.5 mg, S-2.90 2.5 mg,and THF 50 mL

Solution B: S-3730 2.5 mg, S-257 2.5 mg, S-19.8 2.5 mg, S-0.580 2.5 mg,and THF 50 mL

Solution C: S-1470 2.5 mg, S-112 2.5 mg, S-6.93 2.5 mg, S-2.90 2.5 mg,and THF 50 mL

A refractive index (RI) detector is used as the detector.

The glass transition temperature of the resin is preferably −50-20degrees C. and more preferably −35-5 degrees C. When the glasstransition temperature is −50-20 degrees C., blocking resistance is goodand smear fixability and gloss level are improved.

The glass transition temperature is measurable by DSC SYSTEM Q-2000(manufactured by TA INSTRUMENTS. JAPAN). Specifically, about 5.0 mg of aresin placed in an aluminum sample container is set in an instrument toconduct measuring in nitrogen atmosphere under the following conditions.A DSC curve at the second temperature rising is selected and the glasstransition temperature is obtained by the midpoint method.

Measuring Conditions

Hold 5 minutes after cooled down to −70 degrees C.

Raise the temperature to 120 degrees C. at a temperature raising speedof 10 degrees C./min.

Hold 5 minutes after cooled down to −70 degrees C.

Raise the temperature to 120 degrees C. at a temperature raising speedof 10 degrees C./min.

The volume average particle diameter of the resin particle is notparticularly limited and can be suitably selected to suit to aparticular application. The volume average particle diameter ispreferably 10-1,000 nm, more preferably 10-200 nm, and particularlypreferably 10-100 nm to obtain good fixability and image hardness.

The volume average particle diameter can be measured by using, forexample, a particle size analyzer (Nanotrac Wave-UT151, manufactured byMicrotracBEL Corp.).

The proportion of the resin is not particularly limited and can besuitably selected to suit to a particular application. In terms offixability and storage stability of ink, it is preferably 1-30 percentby mass and more preferably 5-20 percent by mass to the total content ofthe ink.

The particle diameter of the solid portion in ink is not particularlylimited and can be suitably selected to suit to a particularapplication. For example, the maximum frequency in the maximum numberconversion is preferably 20-1,000 nm and more preferably 20 to 150 nm toameliorate the discharging stability and image quality such as imagedensity. The solid portion includes resin particles, particles ofpigments, etc. The particle diameter can be measured by using a particlesize analyzer (Nanotrac Wave-UT151, manufactured by MicrotracBEL Corp).

Additive Agent

Ink may further optionally include a surfactant, a defoaming agent, apreservative and fungicide, a corrosion inhibitor, a pH regulator, etc.

Surfactant

Examples of the surfactant are silicone-based surfactants,fluoro-surfactants, amphoteric surfactants, nonionic surfactants,anionic surfactants, etc.

The silicone-based surfactant has no specific limit and can be suitablyselected to suit to a particular application.

Of these, preferred are silicone-based surfactants which are notdecomposed even in a high pH environment.

Specific examples thereof include, but are not limited to,side-chain-modified polydimethylsiloxane, both-distal end-modifiedpolydimethylsiloxane, one-distal-end-modified polydimethylsiloxane, andside-chain-both-distal-end-modified polydimethylsiloxane. Asilicone-based surfactant having a polyoxyethylene group or apolyoxyethylene polyoxypropylene group is particularly preferablebecause such an agent demonstrates good characteristics as an aqueoussurfactant. It is possible to use a polyether-modified silicone-basedsurfactant as the silicone-based surfactant. A specific example thereofis a compound in which a polyalkylene oxide structure is introduced intothe side chain of the Si site of dimethyl silooxane.

Specific examples of the fluoro-surfactants include, but are not limitedto, perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylicacid compounds, ester compounds of perfluoroalkyl phosphoric acid,adducts of perfluoroalkyl ethylene oxide, and polyoxyalkylene etherpolymer compounds having a perfluoroalkyl ether group in its side chain.These are particularly preferable because they do not produce foamseasily.

Specific examples of the perfluoroalkyl sulfonic acid compounds include,but are not limited to, perfluoroalkyl sulfonic acid and salts ofperfluoroalkyl sulfonic acid.

Specific examples of the perfluoroalkyl carboxylic acid compoundsinclude, but are not limited to, perfluoroalkyl carboxylic acid andsalts of perfluoroalkyl carboxylic acid. Specific examples of thepolyoxyalkylene ether polymer compounds having a perfluoroalkyl ethergroup in its side chain include, but are not limited to, salts ofsulfuric acid ester of polyoxyalkylene ether polymer having aperfluoroalkyl ether group in its side chain and salts ofpolyoxyalkylene ether polymers having a perfluoroalkyl ether group inits side chain. Counter ions of salts in these fluoro-surfactants are,for example, Li, Ha, K, NH₄, NH₃CH₂CH₂OH, NH₂(CH₂CH₂OH)₂, andNH(CH₂CH₂OH)₃.

Specific examples of the amphoteric surfactants include, but are notlimited to, lauryl aminopropionic acid salts, lauryl dimethyl betaine,stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.

Specific examples of the nonionic surfactants include, but are notlimited to, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkylesters, polyoxyethylene alkyl amines, polyoxyethylene alkyl amides,polyoxyethylene propylene block polymers, sorbitan aliphatic acidesters, polyoxyethylene sorbitan aliphatic acid esters, and adducts ofacetylene alcohol with ethylene oxides.

Specific examples of the anionic surfactants include, but are notlimited to, polyoxyethylene alkyl ether acetates, dodecyl benzenesulfonates, laurates, and polyoxyethylene alkyl ether sulfates.

These can be used alone or in combination.

The silicone-based surfactants has no particular limit and can besuitably selected to suit to a particular application.

Specific examples thereof include, but are not limited to,side-chain-modified polydimethyl siloxane, both distal-end-modifiedpolydimethylsiloxane, one-distal-end-modified polydimethylsiloxane, andside-chain-both-distal-end-modified polydimethylsiloxane. In particular,a polyether-modified silicone-based surfactant having a polyoxyethylenegroup or a polyoxyethylene polyoxypropylene group is particularlypreferable because such a surfactant demonstrates good characteristicsas an aqueous surfactant.

Any suitably synthesized surfactant and any product thereof available onthe market is suitable. Products available on the market can be obtainedfrom Byc Chemie Japan Co., Ltd., Shin-Etsu Silicone Co., Ltd., DowCorning Toray Co., Ltd., etc., NIHON EMULSION Co., Ltd., KyoeishaChemical Co., Ltd., etc.

The polyether-modified silicon-containing surfactant has no particularlimit and can be suitably selected to suit to a particular application.For example, a compound is usable in which the polyalkylene oxidestructure represented by the following Chemical structure S-1 isintroduced into the side chain of the Si site of dimethyl polysiloxane.

In the Chemical formula S-1 illustrated above, m, n, a, and bindependently represent integers. In addition, R and R′ independentlyrepresent alkyl groups and alkylene groups.

Specific examples of polyether-modified silicone-based surfactantsinclude, but are not limited to, KF-618, KF-642, and KF-643 (allmanufactured by Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602 andSS-1906EX (both manufactured by NIHON EMULSION Co., Ltd.), FZ-2105,FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, and FZ-2164 (allmanufactured by Dow Corning Toray Co., Ltd.), BYK-33 and BYK-387 (bothmanufactured by BYK Japan KK.), and TSF4440, TSF4452, and TSF4453 (allmanufactured by Momentive Performance Materials Inc.).

A fluoro-surfactant in which the number of carbon atoms replaced withfluorine atoms is 2-16 is preferable and, 4 to 16, more preferable.

Specific examples of the fluorosurfactants include, but are not limitedto, perfluoroalkyl phosphoric acid ester compounds, adducts ofperfluoroalkyl ethylene oxide, and polyoxyalkylene ether polymercompounds having a perfluoroalkyl ether group in its side chain.

Of these, polyoxyalkylene ether polymer compounds having aperfluoroalkyl ether group in its side chain are preferable because theydo not produce foams easily and the fluoro-surfactants represented bythe following Chemical formula F-1 or Chemical formula F-2 are morepreferable.

CF₃CF₂(CF₂CF₂)_(m)—CH₂CH₂O(CH₂CH₂O)_(n)H  Chemical formula F-1

As to the compounds represented by Chemical formula F-1, “m” ispreferably 0 or an integer of from 1 to 10 and “n” is preferably 0 or aninteger of from 1 to 40.

C_(n)F_(−2n+1)—CH₂CH(OH)CH₂—O—(CH₂CH₂O)_(a)—Y  Chemical formula F-2

In the compound represented by the chemical formula F-2, Y represents Hor CnF_(2n+1), where n represents an integer of 1-6, orCH₂CH(OH)CH₂—CnF_(2n+1), where n represents an integer of 4-6, orCpH_(2p+1), where p is an integer of 1-19, “a” represents an integer offrom 4 to 14.

As the fluoro-surfactant, products available on the market may be used.

Specific examples of the products available from the market include, butare not limited to, SURFLON S-111, SURFLON S-112, SURFLON S-121, SURFLONS-131, SURFLON S-132, SURFLON S-141, and SURFLON S-145 (all manufacturedby ASAHI GLASS CO., LTD.); FLUORAD FC-93, FC-95, FC-98, FC-129, FC-135,FC-170C, FC-430, and FC-431 (all manufactured by SUMITOMO 3M); MEGAFACEF-470, F-1405, and F-474 (all manufactured by DIC CORPORATION); ZONYLTBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300 UR (all manufacturedby E. I. du Pont de Nemours and Company); FT-110, FT-250, FT-251,FT-400S, FT-150, and FT-400SW (all manufactured by NEOS COMPANYLIMITED); POLYFOX PF-136A, PF-156A, PF-151N, PF-154, and PF-159(manufactured by OMNOVA SOLUTIONS INC.); and UNIDYNE™ DSN-403N(manufactured by DAIKIN INDUSTRIES, Ltd.). Among these, in terms ofimprovement on print quality, in particular coloring property andpermeability, wettability, and uniform dying property on paper, FS-300of E. I. du Pont de Nemours and Company, FT-110, FT-250, FT-251,FT-400S, FT-150, and FT-400SW of NEOS COMPANY LIMITED, POLYFOX PF-151Nof OMNOVA SOLUTIONS INC., and UNIDYNE™ DSN-403N (manufactured by DAIKININDUSTRIES, Ltd.) are particularly preferable.

The proportion of the surfactant in ink is not particularly limited andcan be suitably selected to suit to a particular application. It ispreferably 0.001-5 percent by mass and more preferably 0.05-5 percent bymass in terms of excellent wettability and discharging stability andimprovement on image quality.

Defoaming Agent

The defoaming agent has no particular limit. For example, silicon-baseddefoaming agents, polyether-based defoaming agents, and aliphatic acidester-based defoaming agents are suitable. These can be used alone or incombination. Of these, silicone-based defoaming agents are preferable toeasily break foams.

Preservatives and Fungicides

The preservatives and fungicides are not particularly limited. Aspecific example is 1,2-benzisothiazoline-3-on.

Corrosion Inhibitor

The corrosion inhibitor has not particular limitation. Examples thereofare acid sulfite and sodium thiosulfate.

pH Regulator

The pH regulator has no particular limit. It is preferable to adjust thepH to 7 or higher. Specific examples thereof include, but are notlimited to, amines such as diethanol amine and Methanol amine.

The property of the ink is not particularly limited and can be suitablyselected to suit to a particular application. For example, viscosity,surface tension, pH, etc, are preferable in the following ranges.

Viscosity of ink at 25 degrees C. is preferably 5-30 mPa·s and morepreferably 5-25 mPa·s to improve print density and text quality andobtain good dischargeability.

Viscosity can be measured by, for example, a rotatory viscometer(RE-80L, manufactured by TOM SANGYO CO., LTD.). The measuring conditionsare as follows:

Standard cone rotor (1°34′×R24)

Sample liquid amount: 1.2 mL

Number of rotations: 50 rotations per minute (rpm)

25 degrees C.

Measuring time: three minutes

The surface tension of the ink is preferably 35 mN/m or less and morepreferably 32 mN/m or less at 25 degrees C. in terms that the ink issuitably levelized on a recording medium and the drying time of the inkis shortened.

The pH of the ink is preferably from 7 to 12 and more preferably from 8to 11 in terms of prevention of corrosion of metal materials contactingthe ink.

Recording Medium

The recording medium for use in recording is not particularly limited.Specific examples thereof include, but are not limited to, plain paper,gloss paper, special paper, cloth, film, transparent sheets, printingpaper for general purpose.

Recorded Matter

The recorded matter of the present disclosure includes a recordingmedium and an image formed on the recording medium with the ink of thepresent disclosure.

An inkjet recording device and an inkjet recording method are used torecord the image on the recording medium to obtain the recorded matter.

Ink Container

The ink container of the present disclosure has an ink accommodatingunit to accommodate the ink of the present disclosure and other optionalsuitably-selected members.

There is no specific limit to the container. Any form, any structure,any size, and any material can be suitably selected to suit to aparticular application. For example, a container having at least an inkbag formed of aluminum laminate film, a resin film, etc. can be suitablyused.

Inkjet Recording Device and Inkjet Recording Method

The inkjet recording method of the present disclosure includesdischarging the ink of the present disclosure from nozzles of arecording head and applying the ink to a recording medium for recording.

The inkjet recording device of the present disclosure includes the inkcontainer of the present disclosure, a recording head to discharge inkdroplets, and other optional members.

The ink of the present disclosure can be suitably applied to variousrecording devices employing an inkjet recording method, such asprinters, facsimile machines, photocopiers, multifunction peripherals(serving as a printer, a facsimile machine, and a photocopier), and 3Dmodel manufacturing devices (3D printers, additive manufacturingdevice).

In the present disclosure, the recording device and the recording methodrepresent a device capable of discharging ink, various processingfluids, etc. to a recording medium and a method of recording an image onthe recording medium using the device, respectively. The recordingmedium means an article to which ink or various processing fluids can beattached at least temporarily.

The recording device may further optionally include a device relating tofeeding, conveying, and ejecting the recording medium and other devicesreferred to as a pre-processing device, a post-processing device, etc.in addition to the head portion to discharge the ink.

The recording device and the recording method may further optionallyinclude a heater for use in the heating process and a drier for use inthe drying process. For example, the heating device and the dryingdevice include devices including heating and drying the print surface ofa recording medium and the opposite surface thereof. The heating deviceand the drying device are not particularly limited. For example, a fanheater and an infra-red heater can be used. Heating and drying can beconducted before, during, and after printing.

In addition, the recording device and the recording method are notlimited to those producing meaningful visible images such as texts andfigures with the ink. For example, the recording device and therecording method can produce patterns like geometric design and 3Dimages.

In addition, the recording device includes both a serial type device inwhich the liquid discharging head is caused to move and a line typedevice in which the liquid discharging head is not moved, unlessotherwise specified.

Furthermore, in addition to the desktop type, this recording deviceincludes a wide device capable of printing images on a large recordingmedium such as AO and a continuous printer capable of using continuouspaper wound up in a roll form as recording media.

The recording device of the present disclosure is described using anexample with reference to FIG. 1 and FIG. 2. FIG. 1 is a perspectiveview of the recording device. FIG. 2 is a perspective view of the maintank. An image forming apparatus 400 as an example of the recordingdevice is a serial type image forming apparatus. A mechanical unit 420is disposed in an exterior 401 of the image forming apparatus 400. Eachink accommodating unit 411 of each main tank 410 (410 k, 410 c, 410 m,and 410 y) for each color of black (K), cyan (C), magenta (M), andyellow (Y) is made of a packing member such as aluminum laminate film.The ink accommodating unit 411 is accommodated in, for example, aplastic housing unit 414. As a result, the main tank 410 is used as anink cartridge of each color.

A cartridge holder 404 is disposed on the rear side of the opening whena cover 401 c is opened. The cartridge holder 404 is detachably attachedto the main tank 410. As a result, each ink discharging outlet 413 ofthe main tank 410 communicates with a discharging head 434 for eachcolor via a supplying tube 436 for each color so that the ink can bedischarged from the discharging head 434 to a recording medium.

This recording device may include not only a portion discharging ink butalso a device referred to as a pre-processing device, a post-processingdevice, etc.

As an example of the pre-processing device and the post-processingdevice, as in the case of the ink such as black (K), cyan (C), magenta(M), and yellow (Y), the pre-processing device and the post-processingdevice may further include a liquid accommodating unit including apre-processing fluid and/or a post-processing fluid to discharge thepre-processing fluid and/or the post-processing fluid according to aninkjet printing method.

As another example of the pre-processing device and the post-processingdevice, it is suitable to dispose a pre-processing device and apost-processing device which does not employ the inkjet printing methodbut a blade coating method, a roll coating method, or a spray coatingmethod.

How to use the ink is not limited to the inkjet printing method.Specific examples of such methods other than the inkjet printing methodinclude, but are not limited to, blade coating methods, gravure coatingmethods, bar coating methods, roll coating methods, dip coating methods,curtain coating methods, slide coating methods, die coating methods, andspray coating methods.

The applications of the ink of the present disclosure are notparticularly limited and can be suitably selected to suit to aparticular application. For example, the ink can be used for printedmatter, a paint, a coating material, and foundation. Furthermore, theink can be used to form two-dimensional texts and images and furthermorea three-dimensional solid object (3D modeling object) as a material for3D modeling.

An apparatus for fabricating a three-dimensional object can be any knowndevice with no particular limit. For example, the apparatus includes anink container, a supplying device, and a discharging device, a drier,etc.

The three-dimensional solid object includes an object manufactured byrepeating coating with ink. In addition, the three-dimensional solidobject includes a molded processed product manufactured by processing astructure having a substrate such as a print medium printed with ink.

The molded processed product is fabricated from printed matter or astructure having a sheet-like form, film-like form, etc. by, forexample, heating drawing or punching.

The molded processed product is suitably used for articles which aremolded after surface-decorating. Examples thereof are gauges oroperation panels of vehicles, office machines, electric and electronicdevices, cameras, etc.

Having generally described preferred embodiments of this invention,further understanding can be obtained by reference to certain specificexamples which are provided herein for the purpose of illustration onlyand are not intended to be limiting. In the descriptions in thefollowing examples, the numbers represent weight ratios in parts, unlessotherwise specified.

EXAMPLES

Next, the present disclosure is described in detail with reference toExamples but is not limited thereto.

Synthetic Example 1

Synthesis of Liquid Dispersion 1 of Resin Particle

A mixture of 44 parts of styrene, 53 parts of 2-ethylhexyl acrylate, 1.4parts of AQUALON HS-10 (manufactured by DKS Co. Ltd.), and 50 parts ofdeionized water was emulsified by a HOMOMIXER to obtain a uniform milkwhite emulsified liquid.

87 parts of water having a pH of 3 preliminarily controlled by deionizedwater and sulfuric acid was charged in a 1 L flask equipped with astirrer, a thermometer, a nitrogen introducing tube, and a reflux tubeand heated to 70 degrees C. while introducing nitrogen.

Thereafter, 2.8 parts of aqueous solution of 10 percent by mass AQUALONHS-10 (manufactured by DKS Co. Ltd.) as a reactive emulsifier and 2.7parts of aqueous solution of 5 percent by mass ammonium persulfate werecharged into the flask. Thereafter, the preliminarily preparedemulsified liquid was continuously dripped to the flask in 2.5 hours. Inaddition, 0.6 parts of an aqueous solution of 5 percent by mass ammoniumpersulfate was added every hour until three hours passed since the startof dripping. Subsequent to two-hour aging at 70 degrees C. after thedripping completed, the resultant was cooled down to adjust pH to 7-8 byan aqueous solution of sodium hydroxide to obtain a liquid dispersion 1of resin particle.

Synthesis Example 2

Synthesis of Liquid Dispersion 2 of Resin Particle

A mixture of 41 parts of styrene, 51 parts of 2-ethylhexyl acrylate, 1.9parts of vinyltriethoxy silane, 0.5 parts of 1,6-hexanedioldimethacrylate, 1.4 parts of AQUALON HS-10 (manufactured by DKS Co.Ltd.), and 50 parts of deionized water was emulsified by a HOMOMIXER toobtain a uniform milk white emulsified liquid.

87 parts of water having a pH of 3 preliminarily controlled by deionizedwater and sulfuric acid was charged in a 1 L flask equipped with astirrer, a thermometer, a nitrogen introducing tube, and a reflux tubeand heated to 70 degrees C. while introducing nitrogen.

Thereafter, 2.8 parts of aqueous solution of 10 percent by mass AQUALONHS-10 (manufactured by DKS Co. Ltd.) as a reactive emulsifier and 2.6parts of aqueous solution of 5 percent by mass ammonium persulfate werecharged into the flask. Thereafter, the preliminarily preparedemulsified liquid was continuously dripped to the flask in 2.5 hours. Inaddition, 0.6 parts of an aqueous solution of 5 percent by mass ammoniumpersulfate was added every hour until three hours passed since the startof dripping. Subsequent to two-hour aging at 70 degrees C. after thedripping completed, the resultant was cooled down to adjust pH to 7-8 byan aqueous solution of sodium hydroxide to obtain a liquid dispersion 2of resin particle.

Synthesis Example 3

Synthesis of Liquid Dispersion 3 of Resin Particle

A liquid dispersion 3 of resin particle was obtained in the same manneras in Synthesis Example 2 except that the content of styrene was changedto 40 parts, the content of 2-ethylhexyl acrylate was changed to 50parts, and the content of vinyltriethoxy silane was changed to 3.8parts.

Synthesis Example 4

Synthesis of Liquid Dispersion 4 of Resin Particle

A liquid dispersion 4 of resin particle was obtained in the same manneras in Synthesis Example 2 except that the content of styrene was changedto 39 parts, the content of 2-ethylhexyl acrylate was changed to 49parts, and the content of vinyltriethoxy silane was changed to 5.7parts.

Synthesis Example 5

Synthesis of Liquid Dispersion 5 of Resin Particle

A liquid dispersion 5 of resin particle was obtained in the same manneras in Synthesis Example 2 except that the content of styrene was changedto 38 parts, the content of 2-ethylhexyl acrylate was changed to 48parts, and the content of vinyltriethoxy silane was changed to 7.5parts.

Synthesis Example 6

Synthesis of Liquid Dispersion 6 of Resin Particle

A liquid dispersion 6 of resin particle was obtained in the same manneras in Synthesis Example 3 except that the pH of 87 parts of waterpreliminarily controlled by deionized water and sulfuric acid waschanged to 2.0.

Synthesis Example 7

Synthesis of Liquid Dispersion 7 of Resin Particle A liquid dispersion 7of resin particle was obtained in the same manner as in SynthesisExample 3 except that the pH of 87 parts of water preliminarilycontrolled by deionized water and sulfuric acid was changed to 2.5.

Synthesis Example 8

Synthesis of Liquid Dispersion 8 of Resin Particle

A liquid dispersion 8 of resin particle was obtained in the same manneras in Synthesis Example 3 except that the content of styrene was changedto 39 parts and the content of 1,6-hexanediol dimethacrylate was changedto 0.1 parts.

Synthesis Example 9

Synthesis of Liquid Dispersion 9 of Resin Particle

A liquid dispersion 9 of resin particle was obtained in the same manneras in Synthesis Example 3 except that the content of styrene was changedto 49 parts and the content of 2-ethylhexyl acrylate was changed to 41parts.

Synthesis Example 10

Synthesis of Liquid Dispersion 10 of Resin Particle

A liquid dispersion 10 of resin particle was obtained in the same manneras in Synthesis Example 3 except that the content of styrene was changedto 58 parts and the content of 2-ethylhexyl acrylate was changed to 32parts.

Synthesis Example 11

Synthesis of Liquid Dispersion 11 of Resin Particle

A liquid dispersion 11 of resin particle was obtained in the same manneras in Synthesis Example 3 except that the content of styrene was changedto 31 parts and the content of 2-ethylhexyl acrylate was changed to 59parts.

Synthesis Example 12

Synthesis of Liquid Dispersion 12 of Resin Particle

A mixture of 41 parts of styrene, 53 parts of 2-ethylhexyl acrylate, 1.4parts of AQUALON HS-10 (manufactured by DKS Co. Ltd.) as a reactiveemulsifier, and 50 parts of deionized water was emulsified by aHOMOMIXER to obtain a uniform milk white emulsified liquid.

Thereafter, 80 parts of water having a pH of 3 preliminarily controlledby deionized water and sulfuric acid was charged in a 1 litter flaskequipped with a stirrer, a thermometer, a nitrogen introducing tube, anda reflux tube and heated to 70 degrees C. while introducing nitrogen.Thereafter, 2.8 parts of aqueous solution of 10 percent by mass AQUALONHS-10 (manufactured by DKS Co. Ltd.) as a reactive emulsifier and 5.5parts of aqueous solution of 5 percent by mass ammonium persulfate werecharged into the flask. Thereafter, the preliminarily preparedemulsified liquid was continuously dripped to the flask in 5 hours.

In addition, 1.1 parts of an aqueous solution of 5 percent by massammonium persulfate was added every hour after the start of dripping.

Subsequent to two-hour aging at 70 degrees C. after the drippingcompleted, the resultant was cooled down to adjust pH to 7-8 by anaqueous solution of sodium hydroxide to obtain a liquid dispersion 12 ofresin particle.

Synthesis Example 13

Synthesis of Liquid Dispersion 13 of Resin Particle

A mixture of 38 parts of styrene, 49 parts of 2-ethylhexyl acrylate, 7.5parts of vinyltriethoxy silane, 1.4 parts of AQUALON HS-10 (manufacturedby DKS Co. Ltd.) as a reactive emulsifier, and 50 parts of deionizedwater was emulsified by a HOMOMIXER to obtain a uniform milk whiteemulsified liquid.

Thereafter, 80 parts of water having a pH of 3 preliminarily controlledby deionized water and sulfuric acid was charged in a 1 litter flaskequipped with a stirrer, a thermometer, a nitrogen introducing tube, anda reflux tube and heated to 70 degrees C. while introducing nitrogen.Thereafter, 2.8 parts of aqueous solution of 10 percent by mass AQUALONHS-10 (manufactured by DKS Co. Ltd.) as a reactive emulsifier and 5.5parts of aqueous solution of 5 percent by mass ammonium persulfate werecharged into the flask. Thereafter, the preliminarily preparedemulsified liquid was continuously dripped to the flask in 5 hours. Inaddition, 1.1 parts of an aqueous solution of 5 percent by mass ammoniumpersulfate was added every hour after the start of dripping. Subsequentto two-hour aging at 70 degrees C. after the dripping completed, theresultant was cooled down to adjust pH to 7-8 by an aqueous solution ofsodium hydroxide to obtain a liquid dispersion 13 of resin particle.

Synthesis Example 14

Synthesis of Liquid Dispersion 14 of Resin Particle

A mixture of 31 parts of methylmethacrylate, 59 parts of 2-ethylhexylacrylate, 3.8 parts of vinyltriethoxy silane, 0.5 parts of 1,6-hexanediol dimethacrylate, 1.4 parts of AQUALON HS-10 (manufactured by DKS Co.Ltd.), and 50 parts of deionized water was emulsified by a HOMOMIXER toobtain a uniform milk white emulsified liquid.

87 parts of water having a pH of 3 preliminarily controlled by deionizedwater and sulfuric acid was charged in a 1 litter flask equipped with astirrer, a thermometer, a nitrogen introducing tube, and a reflux tubeand heated to 70 degrees C. while introducing nitrogen.

Thereafter, 2.8 parts of aqueous solution of 10 percent by mass AQUALONHS-10 (manufactured by DKS Co. Ltd.) as a reactive emulsifier and 2.6parts of aqueous solution of 5 percent by mass ammonium persulfate werecharged into the flask. Thereafter, the preliminarily preparedemulsified liquid was continuously dripped to the flask in 2.5 hours. Inaddition, 0.6 parts of an aqueous solution of 5 percent by mass ammoniumpersulfate was added every hour until three hours passed since the startof dripping. Subsequent to two-hour aging at 70 degrees C. after thedripping completed, the resultant was cooled down to adjust pH to 7-8 byan aqueous solution of sodium hydroxide to obtain a liquid dispersion 14of resin particle.

Synthesis Example 15

Synthesis of Liquid Dispersion 15 of Resin Particle

A mixture of 31 parts of methylmethacrylate, 61 parts of 2-ethylhexylacrylate, 1.9 parts of vinyltriethoxy silane, 0.5 parts of 1,6-hexanediol dimethacrylate, 1.4 parts of AQUALON HS-10 (manufactured by DKS Co.Ltd.), and 50 parts of deionized water was emulsified by a HOMOMIXER toobtain a uniform milk white emulsified liquid.

87 parts of water having a pH of 3 preliminarily controlled by deionizedwater and sulfuric acid was charged in a 1 L flask equipped with astirrer, a thermometer, a nitrogen introducing tube, and a reflux tubeand heated to 70 degrees C. while introducing nitrogen.

Thereafter, 2.8 parts of aqueous solution of 10 percent by mass AQUALONHS-10 (manufactured by DKS Co. Ltd.) as a reactive emulsifier and 2.6parts of aqueous solution of 5 percent by mass ammonium persulfate werecharged into the flask. Thereafter, the preliminarily preparedemulsified liquid was continuously dripped to the flask in 2.5 hours. Inaddition, 0.6 parts of an aqueous solution of 5 percent by mass ammoniumpersulfate was added every hour until three hours passed since the startof dripping. Subsequent to two-hour aging at 70 degrees C. after thedripping completed, the resultant was cooled down to adjust pH to 7-8 byan aqueous solution of sodium hydroxide to obtain a liquid dispersion 15of resin particle.

Synthesis Example 16

Synthesis of Liquid Dispersion 16 of Resin Particle

A mixture of 20 parts of methylmethacrylate, 72 parts of 2-ethylhexylacrylate, 1.9 parts of vinyltriethoxy silane, 0.5 parts of 1,6-hexanediol dimethacrylate, 1.4 parts of AQUALON HS-10 (manufactured by DKS Co.Ltd.), and 50 parts of deionized water was emulsified by a HOMOMIXER toobtain a uniform milk white emulsified liquid.

87 parts of water having a pH of 3 preliminarily controlled by deionizedwater and sulfuric acid was charged in a 1 L flask equipped with astirrer, a thermometer, a nitrogen introducing tube, and a reflux tubeand heated to 70 degrees C. while introducing nitrogen. Thereafter, 2.8parts of aqueous solution of 10 percent by mass AQUALON HS-10(manufactured by DKS Co. Ltd.) as a reactive emulsifier and 2.6 parts ofaqueous solution of 5 percent by mass ammonium persulfate were chargedinto the flask. Thereafter, the preliminarily prepared emulsified liquidwas continuously dripped to the flask in 2.5 hours. In addition, 0.6parts of an aqueous solution of 5 percent by mass ammonium persulfatewas added every hour until three hours passed since the start ofdripping. Subsequent to two-hour aging at 70 degrees C. after thedripping completed, the resultant was cooled down to adjust pH to 7-8 byan aqueous solution of sodium hydroxide to obtain a liquid dispersion 16of resin particle.

Synthesis Example 17

Synthesis of Liquid Dispersion 17 of Resin Particle

A mixture of 10 parts of methylmethacrylate, 82 parts of 2-ethylhexylacrylate, 1.9 parts of vinyltriethoxy silane, 0.5 parts of 1,6-hexanediol dimethacrylate, 1.4 parts of AQUALON HS-10 (manufactured by DKS Co.Ltd.), and 50 parts of deionized water was emulsified by a HOMOMIXER toobtain a uniform milk white emulsified liquid.

87 parts of water having a pH of 3 preliminarily controlled by deionizedwater and sulfuric acid was charged in a 1 L flask equipped with astirrer, a thermometer, a nitrogen introducing tube, and a reflux tubeand heated to 70 degrees C. while introducing nitrogen.

Thereafter, 2.8 parts of aqueous solution of 10 percent by mass AQUALONHS-10 (manufactured by DKS Co. Ltd.) as a reactive emulsifier and 2.6parts of aqueous solution of 5 percent by mass ammonium persulfate werecharged into the flask. Thereafter, the preliminarily preparedemulsified liquid was continuously dripped to the flask in 2.5 hours. Inaddition, 0.6 parts of an aqueous solution of 5 percent by mass ammoniumpersulfate was added every hour until three hours passed since the startof dripping. Subsequent to two-hour aging at 70 degrees C. after thedripping completed, the resultant was cooled down to adjust pH to 7-8 byan aqueous solution of sodium hydroxide to obtain a liquid dispersion 17of resin particle.

Next, the solid portion concentration, the volume average particlediameter, and the glass transition temperature of each liquid dispersionof resin particle obtained are shown in Table 1.

The volume average particle diameter was measured by using, for example,a particle size analyzer (Nanotrac Wave-UT151, manufactured byMicrotracBEL Corp.).

The glass transition temperature was measured by DSC SYSTEM Q-2000(manufactured by TA INSTRUMENTS. JAPAN). DSC curve at the secondtemperature rising was selected to obtain the glass transitiontemperature according to the midpoint method.

Measuring Conditions

Hold 5 minutes after cooled down to −70 degrees C.

Raise the temperature to 120 degrees C. at a temperature raising speedof 10 degrees C./min.

Hold 5 minutes after cooled down to −70 degrees C.

Raise the temperature to 120 degrees C. at a temperature raising speedof 10 degrees C./min.

TABLE 1 Concentration of solid portion Volume average Glass transition(percent by particle diameter temperature mass) (nm) (degrees C.) Liquiddispersion 1 38.4 143 −0.6 of resin particle Liquid dispersion 2 38.7145 −5.4 of resin particle Liquid dispersion 3 38.8 151 −5.4 of resinparticle Liquid dispersion 4 38.5 142 −0.5 of resin particle Liquiddispersion 5 39.4 142 −1.4 of resin particle Liquid dispersion 6 39.3146 −4.3 of resin particle Liquid dispersion 7 38.1 139 −2.5 of resinparticle Liquid dispersion 8 38.8 127 0.2 of resin particle Liquiddispersion 9 38.8 126 −4.3 of resin particle Liquid dispersion 10 39.1135 12 f resin particle Liquid dispersion 11 38.3 130 34 f resinparticle Liquid dispersion 12 39.7 133 −0.4 of resin particle Liquiddispersion 13 39.1 152 −1.5 of resin particle Liquid dispersion 14 38.7153 −22 of resin particle Liquid dispersion 15 38.3 13 −25 of resinparticle Liquid dispersion 16 37.0 145 −38 of resin particle Liquiddispersion 17 38.4 138 −58 of resin particle

Preparation Example 1

Preparation of Aqueous Dispersion 1 of Black Pigment-Containing Polymer

Preparation of Polymer Solution

After sufficient replacement with nitrogen gas in a flask equipped witha mechanical stirrer, a thermometer, a nitrogen gas introducing tube, areflux tube, and a dripping funnel, 11.2 g of styrene, 2.8 g of acrylicacid, 12.0 g of lauryl methacrylate, 4.0 g of polyethylene glycolmethacrylate, 0.4 g of mercapto ethanol, and 40 g of methylethyl ketonewere mixed and heated to 65 degrees C.

Next, a liquid mixture of 100.8 g of styrene, 25.2 g of acrylic acid,108.0 g of lauryl methacrylate, 36.0 g of polyethylene glycolmethacrylate, 60.0 g of hydroxyethyl methacrylate, 3.6 g of mercaptoethanol, 2.4 g of azobisdimethyl valeronitrile, and 342 g of methylethylketone was dripped into the flask in two and a half hours. Subsequently,a liquid mixture of 0.8 g of azobismethyl valeronitrile and 18 g ofmethylethyl ketone was dripped into the flask in half an hour. Afterone-hour aging at 65 degrees C., 0.8 g of azobismethyl valeronitrile wasadded and aged for another hour. After the reaction, 800 g of [PolymerSolution] having a concentration of 50 percent by mass was obtained.

Preparation of Aqueous Dispersion 1 of Black Pigment-Containing Polymer

28 g of the [Polymer Solution], 32 g of black pigment (C.I. PigmentBlack 7: Monarch 880, manufactured by Cabot Corporation), 13.6 g of 1mol/L aqueous solution of potassium hydroxide, 20 g of methylethylketone, 13.6 g of deionized water were sufficiently stirred followed bymixing and kneading by a roll mill.

The thus-obtained paste was charged in 200 g of pure water. Subsequentto sufficient stirring, methylethyl ketone and water were distilled awayby using an evaporator to obtain [Aqueous dispersion 1 of blackpigment-containing polymer] having a pigment of 15 percent by mass and asolid portion of 20 percent by mass.

Example 1

Preparation of Ink 1

The liquid mixture having the following recipe was stirred for an hourand mixed uniformly. Thereafter, 33 percent by mass of the [Aqueousdispersion element 1 of polymer containing black pigment] was added anddeionized water was added in such a manner that the total was 100percent by mass followed by stirring for an hour.

Thereafter, the resultant was filtered by a cellulose acetate membranefilter having an average opening of 0.8 μm with an increased pressure toremove coarse particles to obtain Ink 1.

Liquid Mixture Recipe

Liquid dispersion 2 of resin particle: 15 parts Propylene glycol: 30parts 1,3-butane diol: 5 parts 2-ethyl-l,3-hexane diol: 2 parts2,4,7,9-tetramethyl-4,7-decanediol: 0.2 parts Addition reaction productof perfluoroalkyl polyethylene 0.2 parts oxide (DSN-403N, manufacturedby DAIKIN INDUSTRIES, ltd ):

Examples 2 to 10 and Comparative Examples 1 to 7

Preparation of Ink 2-17

Inks 2-17 were manufactured in the same manner as in Example 1 exceptthat Liquid dispersion 2 of resin particle was changed to the liquiddispersions of resin particle shown in Table 2.

Next, an ink cartridge was filled with the thus-obtained inks 1-17 andimages were formed using an inkjet printer (IPSiO GX e5500, manufacturedby Ricoh Company Ltd.) including the ink cartridge.

The images formed as described above were evaluated according to thefollowing criteria: The evaluation results and the measuring results ofdynamic viscoelasticity of the ink film are shown in Tables 2 and 3.

Measuring of Dynamic Elasticity of Ink Film

First, each ink was dried for 48 hours at 100 degrees C. in a constanttemperature tank employing heated wind circulation system to obtain anink film having a thickness of about 0.3 mm, which was cut to a size ofa length of about 30 mm and a width of about 10 mm. Thereafter, the inkfilm was measured by using ARES-G2 (manufactured by TA Instruments) witha freezer. After the sample of the ink film was set in a device at 20degrees C. using a torsion solid clamp as a jig for fixing a sample, thesample was cooled down to −60 degrees C. under an auto tension of 2 g.10 minutes after the temperature reached −60 degrees, the sample wasmeasured under the following conditions. Based on the obtained measuringdata, the storage elastic modulus at 20 degrees C. was defined as G1,the storage elastic modulus at 80 degrees C. was defined as G2, thestorage elastic modulus at −20 degrees C. was defined as G3, and thestorage elastic modulus at −40 degrees C. was defined as G4.

Measuring Conditions

Measuring mode: temperature sweep

Measuring range of temperature: −60-100 degrees C.

Temperature rising speed: 5 degrees C./min

Frequency: 1 Hz

Initial distortion: 0.1 percent

Auto tension: 2 g

Image Density

A solid square black image (100 percent duty) of 10 points with an inkattachment amount of 10,000 mg/m² was printed on gloss paper(LumiArtGross, weight 90 g/m², manufactured by Store Enso) for printingusing the inkjet printer, Image density of the thus-obtained solid imagewas measured using a reflection type color spectrodensitometer(manufactured by X-RITE CORPORATION) and evaluated according to thefollowing criteria:

Evaluation Criteria

E (Excellent): 1.5 or higherG (Good): 1.2 to less than 1.5M (Marginal): 0.9 to less than 1.2P (Poor): Less than 0.9

Gloss Level of Image

60 degree gloss level (Image gloss level) of the black square solidimage printed on the gloss paper (LumiArtGross, weight 90 g/m²,manufactured by Store Enso) for printing by using the inkjet printer wasmeasured by a gloss meter (4501-microgloss 60 degrees, manufactured byBYK Japan KK.) and compared with 60 degree gloss level (background glosslevel) of the background of the gloss paper for printing. The comparisonresults were evaluated according to the following criteria:

60 degree gloss level of the background of the gloss paper for printingwas 25.

Evaluation Criteria

G (Good): Gloss level of image equal to or greater than that of glosslevel of background.P (Poor): Gloss level of image less than that of gloss level ofbackground.

Smearing Fixing Property

Three hours after a solid image was printed on gloss paper(LumiArtGross, weight 90 g/m², manufactured by Store Enso) by the inkjetprinter with 100 duty per 6 cm×6 cm, and an ink attachment amount of10,000 mg/m², white cotton cloth (manufactured by TOYO SEIKI Co., Ltd.)mounted onto a clock meter (manufactured by TOYO SEIKI Co., Ltd.) wasmoved back and forth on the printed solid image portion ten times.Thereafter, the ink contamination level of the white cotton was visuallyobserved to make evaluation according to the following criteria:

Evaluation Criteria

E (Excellent): Free of contaminationG (Good): Contamination observed but causing no practical problemM (Marginal): Slightly substantial contamination observedP (Poor): Substantial contamination observed

Abrasion Resistance

A solid image was printed on gloss paper (LumiArtGross, weight 90 g/m²,manufactured by Store Enso) for printing with an ink attachment amountof 10,000 mg/m²) using the inkjet printer and dried by a heated windcirculation drier for one minute at 100 degrees C. Next, polyurethaneform tape (manufactured by 3M Company) having a thickness of 1.6 mm cutto a size of 1.1 cm square was attached to the friction block of a clockmeter (manufactured by DAIEI KAGAKU SEIKI MFG. co., ltd.). Thereafter,gloss paper for printing cut to a size of 1.0 cm square was attached tothe form tape. With the friction block down to bring the gloss paper forprinting into contact with the solid image portion, the gloss paper wasmoved back and forth 10 times. After moving back and forth, the glosspaper for printing was peeled off together with the form tape. Imagedensity of the image transferred to the gloss paper for printing wasmeasured by using a reflection type color spectrodensitometer(manufactured by X-RITE CORPORATION) and evaluated according to thefollowing criteria:

Evaluation Criteria

E (Excellent): Image density less than 0.1

G (Good): Image density of 0.1 to less than 0.2

M (Marginal): Image density of 0.2 to less than 0.3

P (Poor): Image density of 0.3 or greater

Blocking Resistance

Blocking resistance was evaluated according to TAPPI test T477, issuedby Japan Technical Association of the Pulp and Paper Industry A solidimage of 6 cm square was printed on gloss paper (LumiArtGross, weight 90g/m², manufactured by Store Enso) for printing with an ink attachmentamount of 10,000 mg/m²) using the inkjet printer. Thereafter, glosspaper for printing with no image on the print surface was attached tothe solid image, which was sandwiched by two glass plates each having asize of 10 cm square. Under a load of 1 kg/m², this was left undone for24 hours at 40 degrees C. and 90 percent RH. Thereafter, it was leftundone for two more hours at room temperature (25 degrees C.). Theadhesion degree of the two sheets of gloss sheets when they were peeledoff was observed according to the following evaluation criteria.

Evaluation Criteria

E (Excellent): No blocking (surface of sample free of scratch or scarand no adhesion or sticking to the adjacent surface)

G (Good): Slight blocking occurred (Slight sticking. Slight scarring onthe surface of sample).

M (Marginal): Significant blocking occurred (Sticking or adhesion toadjacent surface. Scarring observed on the surface of sample)

P (poor): Blocking occurred (Adhesion and fusion occurred with adjacentsurface. Difficult to be stripped each other)

TABLE 2 Liquid dispersion G1 G3 G4 of resin [10⁻⁸ [10⁻⁸ [10⁻⁸ Inkparticle Pa] G2/G1 Pa] Pa] Exam- 1 Liquid 2.4 0.44 2.2 2.4 ple 1dispersion 2 of resin particle Exam- 2 Liquid 3.5 0.65 3.6 4.8 ple 2dispersion 3 of resin particle Exam- 3 Liquid 4.7 0.73 2.9 3.3 ple 3dispersion 4 of resin particle Exam- 4 Liquid 3.8 0.66 3.1 3.8 ple 4dispersion 7 of resin particle Exam- 5 Liquid 3.7 0.68 1.9 2.3 ple 5dispersion 8 of resin particle Exam- 6 Liquid 4.5 0.42 3.3 3.7 ple 6dispersion 9 of resin particle Exam- 7 Liquid 3.1 0.54 0.81 1.6 ple 7dispersion 11 of resin particle Exam- 8 Liquid 2.9 0.75 0.77 1.4 ple 8dispersion 14 of resin particle Exam- 9 Liquid 2.6 0.70 0.47 1.3 ple 9dispersion 15 of resin particle Exam- 10 Liquid 2.2 0.69 0.32 1.2 ple 10dispersion 16 of resin particle Compar- 11 Liquid 2.2 0.27 1.4 2.3 ativedispersion Exam- 1 of resin ple 1 particle Compar- 12 Liquid 5.5 0.803.5 4.5 ative dispersion Exam- 5 of resin ple 2 particle Compar- 13Liquid 5.1 0.89 2.7 4.1 ative dispersion Exam- 6 of resin ple 3 particleCompar- 14 Liquid 10.7 0.35 3.2 4.6 ative dispersion Exam- 10 of resinple 4 particle Compar- 15 Liquid 1.6 0.35 2 3.8 ative dispersion Exam-12 of resin ple 5 particle Compar- 16 Liquid 6.2 0.81 2.2 2.8 ativedispersion Exam- 13 of resin ple 6 particle Compar- 17 Liquid 1.8 0.690.27 0.9 ative dispersion Exam- 17 of resin ple 7 particle

TABLE 3 Image Gloss Smear Abrasion Blocking Ink density level fixabilityresistance resistance Example 1 1 G G G G G Example 2 2 E G E G EExample 3 3 G G G G E Example 4 4 G G E G E Example 5 5 E G G G EExample 6 6 G G E G G Example 7 7 E G E E G Example 8 8 G G E E GExample 9 9 G G E E G Example 10 10 G G E G G Comparative 11 M P P P MExample 1 Comparative 12 G G M P E Example 2 Comparative 13 G P M M EExample 3 Comparative 14 M P P P E Example 4 Comparative 15 P P E G PExample 5 Comparative 16 G G P P P Example 6 Comparative 17 M P G M PExample 7

Preparation Example I

Preparation of Pigment Dispersion I

2 mol/litter of sodium persulfate was added to and stirred with 100 g ofcarbon black (#44, nitrogen adsorption specific surface area: 110 m²/g,DBP oil absorption amount: 78 cm³/100 g, manufactured by MitsubishiChemical Corporation) at 75 degrees C. for 10 hours for acidictreatment.

Thereafter, the resultant was washed with pure water and dried anddispersed in water again. The disperooin was neutralized by sodiumhydroxide followed by ultrafiltration membrane to separate the remainingsalt.

Moisture was adjusted in such a manner that the pigment concentrationwas 20 percent by mass. The resultant was filtered with a membranefilter having an average opening diameter of 1.5 μm to remove coarseparticles.

The electroconductivity, pH, and the acid value of the thus-obtainedpigment dispersion was 1.35 mS/cm, 5.6, and 50 mgKOH/g, respectively.The amount of Na contained in 20 percent by mass liquid dispersion was2,200 ppm.

In addition, when the decomposition product separated from the liquiddispersion was condensed and measured by Fourier Transform InfraredSpectroscopy (FT-IR), a peak derived from —COO— was observed around1,590 cm-1 and 1,384 cm-1.

Synthetic Example I

Synthesis of Liquid Dispersion of Resin Particle I

A mixture of 133 parts of methylmethacrylate, 184 parts of 2-ethylhexylacrylate, 2.2 parts of AQUALON HS-10 (manufactured by DKS Co. Ltd.) as areactive emulsifier, and 166 parts of deionized water was emulsified bya HOMOMIXER to obtain a uniform milk white emulsified liquid.

Thereafter, 287 parts of water having a pH of 3 preliminarily controlledby deionized water and sulfuric acid was charged in a 1 litter flaskequipped with a stirrer, a thermometer, a nitrogen introducing tube, anda reflux tube and heated to 70 degrees C. while introducing nitrogen.

Thereafter, 12.7 parts of aqueous solution of 10 percent by mass AQUALONHS-10 (manufactured by DKS Co. Ltd.) as a reactive emulsifier and 8.7parts of aqueous solution of 5 percent by mass ammonium persulfate werecharged into the flask. Thereafter, the preliminarily prepared emulsionwas continuously dripped to the flask in 2.5 hours.

In addition, 1.8 parts of an aqueous solution of 5 percent by massammonium persulfate was added every hour until three hours passed sincethe start of dripping. Subsequent to two-hour aging at 70 degrees C.after the dripping completed, the resultant was cooled down to adjust pHto 7-8 by an aqueous solution of sodium hydroxide to obtain a liquiddispersion of resin particle I.

Synthesis Example II

Synthesis of Liquid Dispersion of Resin Particle II

A mixture of 120 parts of methylmethacrylate, 165 parts of 2-ethylhexylacrylate, 32 parts of vinyltriethoxy silane, 2.2 parts of AQUALON HS-10(manufactured by DKS Co. Ltd.) as a reactive emulsifier, and 166 partsof deionized water was emulsified by a HOMOMIXER to obtain a uniformmilk white emulsified liquid.

Thereafter, 287 parts of water having a pH of 3 preliminarily controlledby deionized water and sulfuric acid was charged in a 1 litter flaskequipped with a stirrer, a thermometer, a nitrogen introducing tube, anda reflux tube and heated to 70 degrees C. while introducing nitrogen.

Thereafter, 9.4 parts of aqueous solution of 10 percent by mass AQUALONHS-10 (manufactured by DKS Co., Ltd.) as a reactive emulsifier and 8.7parts of aqueous solution of 5 percent by mass ammonium persulfate werecharged into the flask. Thereafter, the preliminarily prepared emulsionwas continuously dripped to the flask in 2.5 hours.

In addition, 1.8 parts of an aqueous solution of 5 percent by massammonium persulfate was added every hour until three hours passed sincethe start of dripping.

Subsequent to two-hour aging at 70 degrees C. after the drippingcompleted, the resultant was cooled down to adjust pH to 7-8 by anaqueous solution of sodium hydroxide to obtain a liquid dispersion ofresin particle II.

Synthesis Example III

Synthesis of Liquid Dispersion of Resin Particle III

A liquid dispersion of resin particle III was obtained in the samemanner as in Synthesis Example I except that the content ofmethylmethacrylate was changed to 79 parts and the content of2-ethylhexyl acrylate was changed to 237 parts.

Synthetic Example IV

Synthesis of Liquid Dispersion of Resin Particle IV

A liquid dispersion of resin particle IV was obtained in the same manneras in Synthesis Example I except that the content of methylmethacrylatewas changed to 95 parts and the content of 2-ethylhexyl acrylate waschanged to 222 parts.

Synthetic Example V

Synthesis of Liquid Dispersion of Resin Particle V

A liquid dispersion of resin particle V was obtained in the same manneras in Synthesis Example I except that the content of methylmethacrylatewas changed to 177 parts and the content of 2-ethylhexyl acrylate waschanged to 139 parts.

Synthetic Example VI

Synthesis of Liquid Dispersion of Resin Particle VI

A liquid dispersion of resin particle VI was obtained in the same manneras in Synthesis Example I except that the content of methylmethacrylatewas changed to 187 parts and the content of 2-ethylhexyl acrylate waschanged to 130 parts.

Synthetic Example VII

Preparation Example of Liquid Dispersion of Resin Particle VII

A mixture of 133 parts of methylmethacrylate, 184 parts of 2-ethylhexylacrylate, 2.2 parts of AQUALON HS-10 (manufactured by DKS Co., Ltd.) asa reactive emulsifier, and 166 parts of deionized water was emulsifiedby a HOMOMIXER to obtain a uniform milk white emulsified liquid.

Thereafter, 264 parts of water having a pH of 3 preliminarily controlledby deionized water and sulfuric acid was charged in a 1 litter flaskequipped with a stirrer, a thermometer, a nitrogen introducing tube, anda reflux tube and heated to 70 degrees C. while introducing nitrogen.

Thereafter, 12.7 parts of aqueous solution of 10 percent by mass AQUALONHS-10 (manufactured by DKS Co., Ltd.) as a reactive emulsifier and 17.8parts of aqueous solution of 5 percent by mass ammonium persulfate werecharged into the flask. Thereafter, the preliminarily prepared emulsionwas continuously dripped to the flask in 5 hours. In addition, 3.8 partsof an aqueous solution of 5 percent by mass ammonium persulfate wasadded every hour until three hours passed since the start of dripping.

Subsequent to two-hour aging at 70 degrees C. after the drippingcompleted, the resultant was cooled down to adjust pH to 7-8 by anaqueous solution of sodium hydroxide to obtain a liquid dispersion ofresin particle VII.

Synthetic Example VIII

Preparation of Liquid Dispersion of Resin Particle VIII

A mixture of 133 parts of methylmethacrylate, 183 parts of 2-ethylhexylacrylate, 0.35 parts of n-octanethiol, 2.2 parts of AQUALON HS-10(manufactured by DKS Co. Ltd.) as a reactive emulsifier, and 166 partsof deionized water was emulsified by a HOMOMIXER to obtain a uniformmilk white emulsified liquid.

Thereafter, 264 parts of water having a pH of 3 preliminarily controlledby deionized water and sulfuric acid was charged in a 1 litter flaskequipped with a stirrer, a thermometer, a nitrogen introducing tube, anda reflux tube and heated to 70 degrees C. while introducing nitrogen.

Thereafter, 12.7 parts of aqueous solution of 10 percent by mass AQUALONHS-10 (manufactured by DKS Co. Ltd.) as a reactive emulsifier and 17.8parts of aqueous solution of 5 percent by mass ammonium persulfate werecharged into the flask. Thereafter, the preliminarily prepared emulsionwas continuously dripped to the flask in 5 hours. In addition, 3.8 partsof an aqueous solution of 5 percent by mass ammonium persulfate wasadded every hour until three hours passed since the start of dripping.

Subsequent to two-hour aging at 70 degrees C. after the drippingcompleted, the resultant was cooled down to adjust pH to 7-8 by anaqueous solution of sodium hydroxide to obtain a liquid dispersion ofresin particle VIII.

Synthetic Example IX

Preparation of Liquid Dispersion of Resin Particle IX

A mixture of 133 parts of methylmethacrylate, 184 parts of 2-ethylhexylacrylate, 2.2 parts of AQUALON HS-10 (manufactured by DKS Co. Ltd.) as areactive emulsifier, and 166 parts of deionized water was emulsified bya HOMOMIXER to obtain a uniform milk white emulsified liquid.

Thereafter, 288 parts of water having a pH of 3 preliminarily controlledby deionized water and sulfuric acid was charged in a 1 litter flaskequipped with a stirrer, a thermometer, a nitrogen introducing tube, anda reflux tube and heated to 70 degrees C. while introducing nitrogen.

Thereafter, 12.7 parts of aqueous solution of 10 percent by mass AQUALONHS-10 (manufactured by DKS Co. Ltd.) as a reactive emulsifier and 9.6parts of aqueous solution of 5 percent by mass ammonium persulfate werecharged into the flask. Thereafter, the preliminarily prepared emulsionwas continuously dripped to the flask in 2 hours.

In addition, 2.2 parts of an aqueous solution of 5 percent by massammonium persulfate was added every hour.

Subsequent to two-hour aging at 70 degrees C. after the drippingcompleted, the resultant was cooled down to adjust pH to 7-8 by anaqueous solution of sodium hydroxide to obtain a liquid dispersion ofresin particle IX.

Next, the solid portion concentration and the volume average particlediameter of the liquid dispersion of each resin particle obtained areshown in Table 1.

The volume average particle diameter was measured by using, for example,a particle size analyzer (Nanotrac Wave-UT151, manufactured byMicrotracBEL Corp.).

TABLE I Concentration of Volume average solid portion particle diameter(percent by mass) (nm) Liquid Dispersion of Resin 38.8 149 Particle ILiquid Dispersion of Resin 37.2 146 Particle II Liquid Dispersion ofResin 39.4 145 Particle III Liquid Dispersion of Resin 38.1 144 ParticleIV Liquid Dispersion of Resin 38.8 150 Particle V Liquid Dispersion ofResin 39.1 151 Particle VI Liquid Dispersion of Resin 39.4 146 ParticleVII Liquid Dispersion of Resin 39.5 141 Particle VIII Liquid Dispersionof Resin 38.7 149 Particle IX

Example I

Preparation of Ink

A liquid mixture of the following recipe was stirred for one hour foruniform mixing. Thereafter, the resultant was filtered by a celluloseacetate membrane filter having an average opening of 0.8 μm with anincreased pressure to remove coarse particles to obtain Ink 2.

Ink Recipe

Pigment dispersion I: 5.0 percent by mass (solid portion) Resin particleI: 1.5 percent by mass (solid portion) Resin particle II: 4.5 percent bymass (solid portion) Propylene glycol: 30 percent by mass 1,3-butanediol: 5 percent by mass 2-pyrolidone 2.0 percent by mass Surfactant(SOFTANOL EP7025, 1.0 percent by mass manufactured by Nippon ShokubaiCo., Ltd.): 2,2,4-trimethyl-l,3-pentanediol: 2.0 percent by massDeionized water Rest to 100 percent by mass in total

Examples II to VIII and Comparative Examples I to IX

Preparation of Ink

Inks I and III-XII were prepared in the same manner as in Example Iexcept that the resin particles I and II were changed to the kind andthe amount of the resin particle shown in Table II.

TABLE II Resin particle Content Content (percent (percent by mass bymass of solid of solid Ink Kind portion) Kind portion) Comparative 1Resin particle 1 Resin particle 5 Example 1 1 2 Example 1 2 Resinparticle 1.5 Resin particle 4.5 1 2 Example 2 3 Resin particle 2 Resinparticle 4 1 2 Example 3 4 Resin particle 3 Resin particle 3 1 2Comparative 5 Resin particle 3.5 Resin particle 2.5 Example 2 1 2Comparative 6 Resin particle 2 Resin particle 4 Example 3 3 2 Example 47 Resin particle 2 Resin particle 4 4 2 Example 5 8 Resin particle 2Resin particle 4 5 2 Comparative 9 Resin particle 2 Resin particle 4Example 4 6 2 Example 6 10 Resin particle 2 Resin particle 4 7 2 Example7 11 Resin particle 2 Resin particle 4 8 2 Example 8 12 Resin particle 2Resin particle 4 9 2

Next, an ink cartridge was filled with the thus-obtained Inks I-XII andimages were formed using an inkjet printer (IPSiO GX e5500, manufacturedby Ricoh Company Ltd.) to which the ink cartridge was mounted.

The images formed as described above were evaluated according to thefollowing criteria:

The evaluation results and the measuring results of the content of THFsoluble portion of the ink film, the mass average molecular mass, andthe glass transition temperature were shown in Tables III and IV.

Content of THF Soluble Portion of Resin in Ink Film

First, ink was dried for 1 day at 100 degrees C. in a constanttemperature tank employing heated wind circulation system to obtain anink film having a thickness of about 0.3 mm, which was cut to a size ofa length of about 50 mm and a width of about 10 mm.

The ink film cut to the size was dipped in 50 g of deionized water andmaintained at 50 degrees C. for one day. Thereafter, the ink film wastaken out from the deionized water and dried at 50 degrees C. for oneday.

Next, about 30 mg of the ink film subjected to dipping treatment withdeionized water was placed in an aluminum sample container, which wasset in a thermogravimetric analyzer (SHIMADZU DTG-60, manufactured byShimadzu Corporation), and measured in a nitrogen atmosphere in thefollowing conditions.

Measuring Conditions

Temperature was raised from 40 to 100 degrees C. as a temperature risingspeed of 10 degrees/minute.

Maintained at 100 degrees C. for 10 minutes

Temperature was raised from 100 to 500 degrees C. as a temperaturerising speed of 10 degrees/minute.

Maintained at 500 degrees C. for 10 minutes

Thereafter, based on the obtained measuring results, the content R(percent by mass) of the resin in the ink film can be calculated fromthe mass M1 (mg) obtained after 10 minutes at 100 degrees C. and themass M2 (mg) obtained after 10 minutes at 500 degrees C.

R=(M1−M2)/M1×100

1 g of the dried film obtained after dipping treatment with deionizedwater was dipped in 10 g of THF and maintained at room temperature forone day.

The supernatant of the dip coated liquid was dried at 150 degrees C. for3 hours in a drier and the THF soluble portion (percent) of the resin inthe dried film was calculated assigning the masses before and afterdrying into the following relation.

In the following relation, M3 (g) was the mass of the dried film dippedin THS, M4 (g) is the mass of THF for use in dipping the dried film, M5(g) is the mass of the supernatant of the dried dipping liquid, and M6(g) was the mass after drying.

T=(M4×M6)/(M3×M5)×100

Based on the content R of the resin in the ink film and the THF solubleportion T (percent) of the resin in the dried film, the THF solubleportion of the resin contained in the dried film obtained by drying theink of the present disclosure is calculated according to the followingrelation.

THF soluble portion of the resin contained in the dried film obtained bydrying the ink of the present disclosure=T/R×100

Mass Average Molecular Mass of THF Soluble Portion

The mass average molecular mass of the THF soluble portion was measuredby using a gel permeation chromatography (GPC) measuring instrument(HLC-8220 GPC, manufactured by TOSOH CORPORATION).

The column used was TSKgel Super HZM-M 15 cm triplet (manufactured byTOSOH CORPORATION).

The resin to be measured was dissolved in THF to obtain a 0.15 percentby mass THF solution (including a stabilizer, manufactured by WAKO PURECHEMICAL INDUSTRIES, LTD.) followed by filtration using a filter havingan opening of 0.2 μm. The resultant filtrate was used as a sample.

100 μl of the THF sample solution was injected into the measuringinstrument under the condition that the temperature was 40 degrees C.and the flow speed was 0.35 ml/min.

The mass average molecular mass of the THS soluble portion wascalculated by using a standard curve created by a mono-dispersedpolystyrene standard sample.

As the mono-dispersed polystyrene standard sample, Showdex STANDARDSERIES (manufactured by SHOWA DENKO K.K.) and toluene were used.

THF solutions of the following three kinds of mono-dispersed polystyrenestandard samples were prepared and the measuring was conducted under theconditions specified above to create a standard curve by defining themaintaining time of the peak top as the light scattering molecular massof the mono-dispersed polystyrene standard samples.

Solution A: S-7450 2.5 mg, S-678 2.5 mg, S-46.5 2.5 mg, S-2.90 2.5 mg,and THF 50 mL

Solution B: S-3730 2.5 mg, S-257 2.5 mg, S-19.8 2.5 mg, S-0.580 2.5 mg,and THF 50 mL

Solution C: S-1470 2.5 mg, S-112 2.5 mg, S-6.93 2.5 mg, S-2.90 2.5 mg,and THF 50 mL

A refractive index (RI) detector is used as the detector.

Glass Transition Temperature of THF Soluble Portion

The glass transition temperature of the THF soluble portion was measuredby DSC SYSTEM Q-2000 (manufactured by TA INSTRUMENTS, JAPAN).

Specifically, about 5.0 mg of the THF soluble portion of the resinplaced in an aluminum sample container was set in an instrument toconduct measuring in nitrogen atmosphere under the following conditions.

A DSC curve at the second temperature rising was selected and the glasstransition temperature was obtained by the midpoint method.

Hold 5 minutes after cooled down to −70 degrees C.

Raise the temperature to 120 degrees C. at a temperature raising speedof 10 degrees C./min.

Hold 5 minutes after cooled down to −70 degrees C.

Raise the temperature to 120 degrees C. at a temperature raising speedof 10 degrees C./min.

Image Density

A solid square black image (100 percent duty) of 10 points with an inkattachment amount of 10,000 mg/m² was printed on gloss paper(LumiArtGross, weight 90 g/m², manufactured by Store Enso) for printingusing the inkjet printer. Image density of the thus-obtained solid imagewas measured using a reflection type color spectrodensitometer(manufactured by X-RITE CORPORATION) and evaluated according to thefollowing criteria:

Evaluation Criteria

G (Good): 1.5 or higherM (Marginal): 1.2 to less than 1.5P (Poor): Less than 1.2

Gloss Level of Image

60 degree gloss level (Image gloss level) of the black square solidimage printed on the gloss paper (LumiArtGross, weight 90 g/m²,manufactured by Store Enso) for printing by using the inkjet printer wasmeasured by a gloss meter (4501-microgloss 60 degrees, manufactured byBYK Japan KK.) and compared with 60 degree gloss level (background glosslevel) of the background of the gloss paper for printing. The comparisonresults were evaluated according to the following criteria:

60 degree gloss level of the background of the gloss paper for printingwas 25.

Evaluation Criteria

G (good): Background gloss level+2<Image gloss levelM (marginal): Background gloss level≤Image gloss level≤background glosslevel+2P (poor): Image gloss level<Background gloss

Smearing Fixing Property

Three hours after a solid image was printed on gloss paper(LumiArtGross, weight 90 g/m², manufactured by Store Enso) by the inkjetprinter with 100 duty per 6 cm×6 cm, and an ink attachment amount of10,000 mg/m², white cotton cloth (manufactured by TOYO SEIKI Co., Ltd.)mounted onto a clock meter (manufactured by TOYO SEIKI Co., Ltd.) wasmoved back and forth on the printed solid image portion ten times.Thereafter, the ink contamination level of the white cotton was visuallyobserved to make evaluation according to the following criteria:

Evaluation Criteria

G (Good): Free of contaminationM (Marginal): Contamination observed but causing no practical problemP (Poor): Substantial contamination observed

Blocking Resistance

Blocking resistance was evaluated according to TAPPI test T477, issuedby Japan Technical Association of the Pulp and Paper Industry

A solid image of 6 cm square was printed on gloss paper (LumiArtGross,weight 90 g/m², manufactured by Store Enso) for printing with an inkattachment amount of 10,000 mg/m²) using the inkjet printer. Thereafter,gloss paper for printing with no image on the print surface was attachedto the solid image, which was sandwiched by two glass plates each havinga size of 10 cm square. Under a load of 1 kg/m², this was left undonefor 24 hours at 40 degrees C. and 90 percent RH.

Thereafter, it was left undone for two more hours at room temperature(25 degrees C.). The adhesion degree of the two sheets of gloss sheetswhen they were peeled off was observed according to the followingevaluation criteria.

Evaluation Criteria

G (Good): No blocking (surface of sample free of scarring with noadhesion or sticking to the adjacent surface)M (Marginal): Slight blocking occurred (Slight sticking. Slight scarringon the surface of sample).P (Poor): Significant blocking occurred (Sticking or adhesion toadjacent surface. Scarring observed on the surface of sample)

TABLE III Glass transition Content (percent temperature Mass average bymass) of THF (degrees C.) of molecular mass of soluble portion of THFsoluble THF soluble Ink resin in ink film portion portion Example 1 222.6 −1.6 520,000 Example 2 3 32.1 0.6 610,000 Example 3 4 46.8 −1.1590,000 Example 4 7 33.4 −17.9 480,000 Example 5 8 30.7 17.2 630,000Example 6 10 35.2 −3.1 300,000 Example 7 11 44.1 −3.5 140,000 Example 812 26.6 1.2 910,000 Comparative 1 18.2 −3.7 510,000 Example 1Comparative 5 56.5 −0.7 560,000 Example 2 Comparative 6 31.5 −23.1440,000 Example 3 Comparative 9 28.7 22.5 570,000 Example 4

TABLE IV Image Smear Blocking Ink density Gloss level fixabilityresistance Example 1 2 G G G G Example 2 3 G G G G Example 3 4 M M G MExample 4 7 G G G M Example 5 8 G G M G Example 6 10 G M G G Example 711 M M G M Example 8 12 G G M G Comparative 1 G G P G Example 1Comparative 5 P P G G Example 2 Comparative 6 G G G P Example 3Comparative 9 G G P G Example 4

According to the present invention, an ink is provided with which imageshaving good abrasion resistance, good blocking resistance, excellentgloss, and high image density are produced.

Having now fully described embodiments of the present invention, it willbe apparent to one of ordinary skill in the art that many changes andmodifications can be made thereto without departing from the spirit andscope of embodiments of the invention as set forth herein.

1: An ink comprising: a solvent; and a resin, wherein a ratio of atetrahydrofuran soluble portion in the resin present in the ink film is20 to 50 percent by mass to the resin present in the ink film at roomtemperature and a glass transition temperature of the tetrahydrofuransoluble portion is −20 to 20 degrees C. as measured by differentialscanning calorimetry. 2: The ink according to claim 1, wherein a storageelastic modulus G3 of an ink film obtained by drying the ink is 1.0×10⁹Pa or greater at −20 degrees C. as measured by a dynamic viscoelasticitymeasuring method. 3: The ink according to claim 2, wherein a storageelastic modulus G3 of the ink film at −20 degrees C. as measured by thedynamic viscoelasticity measuring method is 4.0×10⁸ Pa to less than1.0×10⁹ Pa and a storage elastic modulus G4 of the ink film at −40degrees C. as measured by the dynamic viscoelasticity measuring methodis 1.0×10⁹ Pa or greater.
 4. (canceled) 5: The ink according to claim 1,wherein a mass average molecular mass of a tetrahydrofuran solubleportion of the resin present in the ink film is 200,000-900,000 asmeasured by gel permeation chromatography. 6: The ink according to claim1, wherein a tetrahydrofuran insoluble portion of the resin present inthe ink film is cross-linked. 7: The ink according to claim 1, whereinthe resin includes a resin particle including an acrylic resin or astyrene resin. 8: The ink according to claim 1, wherein the resinincludes a structure derived from a reactive emulsifier. 9: An inkcontainer comprising: the ink of claim 1; and an ink accommodating unitto accommodate the ink of claim
 1. 10: An inkjet recording methodcomprising: discharging the ink of claim 1 from nozzles of a recordinghead; and applying the ink to a recording medium for recording. 11: Aninkjet recording device comprising: the ink container of claim 9; and arecording head configured to discharge ink droplets. 12: Recorded mattercomprising: a recording medium; and an image formed on the recordingmedium with the ink of claim
 1. 13: The ink according to claim 1,further comprising a pigment, wherein a particle diameter of the pigmentis from 20 to 500 nm. 14: The ink according to claim 1, wherein asurface tension of the ink is 35 mN/s or less.